1. Field of the Invention
The present invention relates to movable body apparatuses, exposure apparatuses and device manufacturing methods, and more particularly to a movable body apparatus that is suitable as an apparatus to move a specimen such as a wafer or a glass plate, an exposure apparatus equipped with the movable body apparatus, and a device manufacturing method that uses the exposure apparatus.
2. Description of the Background Art
Conventionally, in a lithography process for manufacturing electron devices (microdevices) such as semiconductor devices (integrated circuits or the like) or liquid crystal display elements, an exposure apparatus such as a projection exposure apparatus by a step-and-repeat method (a so-called stepper), or a projection exposure apparatus by a step-and-scan method (a so-called scanning stepper (which is also called a scanner)) is mainly used. This type of the projection exposure apparatus has a stage device that holds a substrate such as a wafer or a glass plate (hereinafter, generically referred to as a wafer) and drives the wafer along a predetermined two-dimensional plane.
In order to perform high-precision exposure, the high-precision positional controllability of a stage is required for the stage device, and in order to improve throughput of the exposure operation, higher speed and higher acceleration of the stage are also required. To cope with these requirements, in recent years, a stage device that controls the position of a wafer within a two-dimensional plane using a planar motor by an electromagnetic force drive method has been developed (e.g. refer to U.S. Pat. No. 6,437,463).
In this case, in the stage device disclosed in U.S. Pat. No. 6,437,463, since the planar motor is configured of a stator embedded in the upper section of a base and a mover fixed to the bottom portion of a substrate table that holds a wafer, a drive force used to drive the substrate table acts between the bottom surface of the substrate table and the upper surface of the base. Meanwhile, the position of the center of gravity in the Z-axis direction of the substrate table that is subject to drive of the planar motor is higher than the bottom surface of the substrate table, and therefore, at the time of drive of the substrate table, there is a possibility that the moment around an axis that is orthogonal to the movement direction (the so-called pitching moment) is generated and the operation of the substrate table is destabilized.